Planning timing and method of birth
Up to 60% of twins and more triplets and higher-order pregnancies deliver preterm (i.e. before 37 weeks’ gestation). For those that are undelivered, appropriate timing of delivery is aimed at optimizing gestation but avoiding stillbirth.
For triplets and higher orders, it is rare to get beyond 35 weeks’ gestation. Epidemiological studies show that perinatal mortality of twins increases significantly after 37 weeks’ gestation. Therefore, for uncomplicated twin pregnancies delivery should be considered from 37 weeks’ gestation. A recent systematic review concluded that elective delivery from 36 completed weeks may be the best current strategy to decrease fetal mortality in MCDA twins, and from 37 weeks for uncomplicated dichorionic twins (106).The United Kingdom NICE guideline recommends delivery of dichorionic twins from 37 completed weeks’ gestation, monochorionic twins from 36 completed weeks’ gestation, and triplets from 35 weeks’ gestation. For monochorionic twin pregnancies complicated by TTTS, it is reasonable to offer delivery after 34 weeks' gestation. If a monochorionic twin pregnancy is complicated by sIUGR, timing of delivery would be guided by alteration in the pattern of fetal Doppler (ductus venosus) or changes on computerized fetal monitoring (short-term variation or decelerations). If the Doppler pattern remains stable, then delivery can be planned around 34-36 weeks for type I sIUGR and by 32 weeks for types II and III sIUGR (3). It is important to counsel parents that in sIUGR and TTTS (even after apparently successful treatment) there can be acute transfusional events and despite regular monitoring, there may still be adverse perinatal outcomes. For women who decline elective birth, it is recommended to offer weekly appointments with the specialist obstetrician. At each appointment, offer an ultrasound scan, and perform weekly biophysical profile assessments and fortnightly fetal growth scans (3, 11) (Table 20.2).
Table 20.2 Schedule for specialist antenatal appointments in multiple pregnancy
| Type of multiple pregnancy (uncomplicated) | Minimum contacts with core multidisciplinary team | Timing of appointments plus scans | Additional appointments without scans |
| MCDA | 9a | Approximately 11 *0-13*6 weeks and 16, 18, 20, 22, 24, 28, 32, 34 weeks | - |
| DCDA | 8a | Approximately 11 *0-13*6 weeks and 20, 24, 28, 32, and 36 weeks | 16 and 34 weeks |
| MCTA and DCTA triplets | 11a | Approximately 11 *0-13*6 weeks and 16, 18, 20, 22, 24, 26, 28, 30, 32, and 34 weeks | - |
| DCTA triplets | 7a | Approximately 11 *0-13*6 weeks and 20, 24, 28, 32, and 34 weeks | 16 weeks |
a Including two visits with an obstetrician
Source data from National Institute for Health and Clinical Excellence. Multiple pregnancy: the management of twin and triplet pregnancies in the antenatal period. (Clinical guideline 129.) 2011. http://www.nice.org.uk/CG129. Last accessed 16 April 2016.
The absolute indications for caesarean section in a multiple pregnancy include monoamniotic twins, conjoined twins and triplets, or higher-order multiples (107). Most clinicians would recommend a caesarean section if the first twin is non-vertex in presentation, due to concerns about locked twins and the associated morbidity and mortality (107, 108).